1. Field of the Invention
The present invention relates to a wireless communication data recording medium such as a wireless communication IC card supplied with power in a wireless manner using a radio wave for transmitting and receiving data, and a method of data transmission.
2. Description of the Related Art
In recent years, in order to improve the reliability of the IC cards as a data storing medium, a wireless communication IC card has been proposed for transmitting and receiving data and power in a wireless manner using a radio wave. Such a wireless communication IC card (hereinafter referred to simply as "the IC card") has two antennas built therein for receiving two different carriers transmitted using two radio waves of different frequencies, one for supplying power and the other for transmitting data modulated by the PSK (Phase Shift Keying) modulation scheme, for example. In the process, in order to prevent the power carrier from having an effect on the data transmission, the frequencies of the two carrier waves are sufficiently separated from each other or a filter of a large attenuation is inserted for removing the power carrier from the data carrier.
As described above, the conventional IC card is required to have two antennas, one for receiving a power carrier and one for a data transmission carrier. Also, a filter is required for removing the effect of the power carrier on the data carrier. The result is a number of components having a time constant of an analog circuit, so that it is difficult to configure the circuit on semiconductor integrated circuits (introduction of LSI). This in turn makes it difficult to reduce the circuit size on the one hand and to realize a small package on the other hand.